How Are Piston Rings Made? How Are Piston Rings Manufactured?

In this article we’ll cover how piston rings are made. Piston ring production methods. Making piston rings on a lathe. Making piston rings with a hydraulic press and blanking die. What piston ring material is. We’ll look at what materials piston rings are made from.

How Are Piston Rings Made

Piston rings are made by turning rings out of hollow cylindrical cast-iron blocks obtained by ordinary or centrifugal casting. The inside and outside of these rings are turned to some degree. During this turning, care must be taken that the inner diameter is smaller, and the outer diameter larger, than the actual piston ring diameter.

After this, a piece of length e is cut from these rings. The rings are closed back up and mounted on the lathe with a special fixture. Magnetic lathe chucks are also used for this mounting. The rings are turned to achieve the actual piston ring diameter, height, and width. The faces of the rings (piston rings) obtained this way are then ground to bring them into a usable condition.

The inner diameters of small-diameter piston rings are turned in advance to the required size. Their outer diameters are made oversized. After a suitable e-length piece is cut from the rings, they are closed and mounted on the lathe. They are turned until the outer diameter, height, and width dimensions are achieved. After the side faces are also ground, the manufacture of the piston rings is complete.

Producing Retaining Rings with Blanking Dies

Retaining rings are generally obtained by cutting with blanking dies on press machines. During manufacture, retaining rings must not deform, their surfaces must be flat and smooth, and there must be no defects such as burrs, cracks, or pitting on the surfaces. The sharp edges of retaining rings must be deburred. For this, the cutting edges of the die and punch must be as smooth as possible.

Although piston rings can also be made by casting them individually, rings obtained by cutting them out of cast blocks are more commonly used.

Piston rings are made in two types: cylindrical and eccentric. Cylindrical piston rings have the same thickness all the way around their circumference. In eccentric piston rings, the section opposite the ring gap is made thicker. This is done to provide better flexibility.

The end gaps of piston rings used in automobile engines are generally cut straight. However, in some heavy-duty type engines, this gap section can be made angled, stepped (overlapping), or of a sealed type.

What Materials Are Piston Rings Made From?

Piston rings are generally made from soft cast iron. There are also ones made from steel and bronze.

The fine-grained soft cast iron from which the piston ring is made must be softer than the cylinder material. This ensures that the cylinder wears more slowly. Piston rings made from cast iron gain an excellent polish within a short running-in period, so their frictional resistance decreases significantly. In some fast-running steam engines, cast iron, steel, or bronze piston rings are coated with a bearing metal to reduce frictional resistance.

Piston rings made from soft cast iron are generally used in the pistons of steam engines and internal combustion engines.